1. Technical Field
This invention relates in general to integrated lead suspensions for hard disk drives and in particular to fabricating and applying non-homogenous laminate materials to an integrated lead suspension with a flexure motion limiter.
2. Background Art
In hard disk drive manufacturing, one type of head gimbal assembly has an integrated lead suspension (ELS). An ILS is typically formed by laminating several layers of material together and then selectively etching the layers to achieve a desired architecture. Alternatively, the layers may be formed by plating them on top of one another. These layers usually comprise at least one of each of the following: a stainless steel substrate or support layer, an insulation layer such as a polyimide, and a conductor layer such as copper. An ILS with a bent lead type design must be etched on both sides to clear the polyimide on the bent lead. This step requires additional process time and adds cost to the suspension.
For an ILS with a pico format magnetic read/write head or slider, a flexure motion limiter is often required for damage prevention and dynamic performance. The flexure motion limiter requires forming the stainless steel on either the flexure or the load beam. The formed part is then interleaved with the unformed part at assembly to provide motion limitation on the flexure. This extra forming step and assembly interleave step will add cost and sometimes increase the height profile of the ILS. An improved method for manufacturing integrated lead suspensions is needed to address these issues.
An integrated lead suspension is formed from a laminate of three materials in a variety of configurations having from three to five layers. The materials are stainless steel, polyimide and copper. Each layer is essentially homogeneous, but may be formed with one or more holes or voids prior to the formation of the laminate. After the copper layer is etched to form a tab which overhangs the steel layer, the suspension is welded to a load beam. The load beam prevents the downward motion of the suspension. The tab acts as a flexure motion limiter for upward motion of the suspension. The voids allow a precise amount of polyimide undercut between the steel and copper layers which otherwise could not be achieved.